I think it's avoidable to a certain extent. You can introduce her with the nickname you like and people will follow suit. Once she's in school though, she might want to switch it up! I'm in the same boat, I love a name but dislike the common nicknames so I will be introducing her with a nickname I enjoy to family and friends!

I know (of) two Matildas - one goes by Matty, the other Tilda. The one that goes by Matty uses her full name quite a bit though, while Tilda goes by Tilda almost exclusively. I think Tilly and Tilda are just as intuitive as Matty/Mattie, if not more, and Milly is a good option that isn't too much of a stretch either. It's definitely avoidable, but I think you'd need to choose an alternative nickname, so you can reinforce it before she starts school and other kids call her Matty. If they hear you saying "Bye, Tilly" in the playground in the morning they'll call her Tilly as a nickname, or whatever you choose to use.

I understand your pain it is awful to introduce yourself by your first name only to have that person immediately and without asking call you by a nickname. It urked me so much that I decided to use my middle name.

In your case I would introduce the baby as Matilda and make it known that her nn is Tilly and I would make a strong point of it to anyone who oversteps the mark and calls her Mattie, it is so annoying.

I really think that any nickname is avoidable if you want it to be. My sister's name is MaryCatherine...not M.C., not Mary, not MaryKate...MaryCatherine. Every time someone called her something other than MaryCatherine she or a family member would correct them and eventually everyone who knew her knew what she wanted to be called.

I think if you want a little Matilda, then that is exactly what you will have. If someone calls her Mattie just say "we prefer Matilda" and I can't imagine anyone would go against your wishes.

If you introduce her as "Matilda" and people then call her "mattie" just correct them.

However, be warned that its possible your daughter herself might want to be called "Mattie". This may never happen. But if you honestly cannot stand even the thought that she might ask you one day to only call her Mattie...then perhaps the name isn't for you.